Ni_n(n≤8)团簇的结构(英文)

用高斯程序的B3LYP交换相关函数和全电子基组DGDZVP、TZVP优化Nin、Ni+n和Ni-n(n=2～8),得到这些体系的基态几何构型、离化能、电子亲和能及键能.结果表明:Ni2,Ni3,Ni4,Ni5和Ni6团簇的基态分别是5,7,9,11和13重态.表明:Ni2,Ni3,Ni4,Ni5和Ni6团簇中分别有4,6,8,10和12个平行自旋的电子,在每一个Nin团簇中非耦合的电子最多,这些电子占据不同的轨道,导致每一个Nin团簇的能量最小,说明在这些Nin团簇中电子平行的效应大于电子耦合的效应,这显然与d电子的离域效应有关,称为自旋极化效应,符合宏特规则.Nin、Ni+n和Ni-(n=2～8)体系的磁矩分别是Ni具有8μ(n=6～8),Ni+具有9μ(n=6～8),Ni-具有7μ(n=4～8).

Structure of Small Nin (n≤8) Clusters

Density functional theory B3LYP are performed in study on structure of Nin,Ni+n and Ni-n(n=2-8).DGDZVP all-electron basis sets and TZVP all-electron basis sets are employed.Equilibrium geometries,ionization potentials,electron affinities and binding energies are obtained.It shows that the ground state of Ni2,Ni3,Ni4,Ni5 and Ni6 cluster are 5-,7-,9-,11-,and 13-multiple state,respectively,which indicates spin polarization effect in Nin(n≤8) clusters is important.That is,there are 4,6,8,10,and 12 parallel spin electrons in Ni2,Ni3,Ni4,Ni5 and Ni6 cluster,respectively.Number of non-conjugated electrons in ground state cluster is the greatest.These electrons occupy different spacious orbitals so that energy of Nin(n≤8) cluster is minimized.It can be concluded that effect of parallel spin in Nin(n≤8) clusters is greater than effects of conjugated clusters,which is obviously related to electron d delocalization.This is spin polarization effect of Nin(n≤8) clusters,which is a result of the Hund’s rule.Moreover,we find that spin magnetic moments of Nin(n=6-8) are 8 μB,those of Nin+(n=6-8) are 9 μB and those of Ni-n(n=4-10) are 7 μB.